1. Field of the Invention
The present invention relates to tools which are used to impart rotational motion to mechanical elements and more particularly to a socket drive wrench which provides clockwise and counterclockwise ratcheting as well as freewheeling and lockup modes.
2. Description of the Contemporary and/or Prior Art
The need for and application of tools which impart rotational motion to mechanical elements, such as bolts, is well known. Tools which accomplish this function, in the simpliest form, may take the shape of open-ended or box wrenches. When such tools are used, clearance for 360.degree. rotation must be available for the tool or the tool must be constantly disengaged from a bolt or the like that is being rotated and reengaged therewith to function within limited space. In many instances, disengagement and reengagement is quite burdensome because of limited access. In order to overcome this problem, the so called "ratchet wrench" or "socket drive wrench" has evolved.
In its basic form, these ratchet type wrenches permit a portion thereof, usually a "socket" to engage the head of a bolt or the like and permit the socket to ratchet relative to a handle so that a bolt can be loosened or tightened through oscillation of the handle, without disengagement from the bolt. The earliest models of such wrenches only permitted ratcheting in one direction and had to be flipped over or otherwise modified to provide ratcheting in a second direction. Before too long, wrenches which could be switched from clockwise to counterclockwise ratcheting appeared. This is usually accomplished through a dual pawl mechanism such as the types shown in U.S. Pat. Nos. 295,797 issued to Osborn on Mar. 25, 1884; 335,481 issued to Rettberg on Feb. 2, 1886; and 462,995 issued to Poe on Nov. 10, 1891; each of these devices employing single toothed pawls.
Clockwise and counterclockwise rotation in ratchet wrenches or similar tools through the use of a pair of multitoothed pawls, which provide more positive engagement than a single toothed pawl, is shown in U.S. Pat. Nos. 878,657 issued to Munch on Feb. 11, 1908; 1,157,427 issued to Seivert on Nov. 19, 1915; 2,521,419 issued to Sellers on Sept. 5, 1950; 2,660,910 issued to Sellers on Dec. 1, 1953; 2,982,161 issued to Angquist on May 2, 1961; 3,290,969 issued to Bergquist on Dec. 13, 1966; 3,436,992 issued to Over on Apr. 8, 1969; and 3,342,229 issued to Janes on Sept. 19, 1967. Each of these devices employs a control means which is mounted on the head portion of the device and which is used to shift from use of a clockwise to a counterclockwise pawl. The configurations of Angquist and Bergquist, as well as Over, are quite representative of the head type controls widely available on socket wrenches in the marketplace. While quite convenient to use in many applications, several fundamental disadvantages of such configurations exist. If the socket drive wrench is employed to turn a bolt in a tight location, it is quite frequently very difficult to turn the actuator or control which switches the wrench from clockwise to counterclockwise ratcheting without removal of the wrench from the bolt or the like which is being turned. Additionally, the majority of available socket or ratchet wrenches do not permit freewheeling of the drive portion thereof so that the socket mounted thereon can be freely rotated to facilitate initial engagement with the head of a bolt or the like and ancillary rotation of the bolt after the loosening or prior to the tightening thereof. Another disadvantage of these configurations is they do not permit socket drive lockup so that the wrench can be used as a "breaker bar" where no rotation of the socket is permitted relative to the handle portion thereof. As a result, a mechanic must purchase a second tool, commonly known as a breaker bar, to avail himself of this desirable function.
The aforenoted shortcomings of the particular type of socket drive wrenches discussed have been addressed to some degree in the prior art, but are usually solved by complex apparatuses which are fragile, employ numerous components, and/or are expensive to manufacture.
Handle mounted controls for ratchet wrenches and the like are shown in U.S. Pat. Nos. 766,577 issued to Ansorge on Aug. 2, 1904; 846,360 issued to Sprowls on Mar. 5, 1907; 3,608,402 issued to Rainey on Sept. 28, 1971; 2,851,914 issued to Zeckzer on Sept. 16, 1958. Sprowls employs a single pawl which normally engages the ratchet wheel of the wrench thereof and can be retracted by a handle mounted control to permit freewheeling. Ansorge has a pawl which is normally out of engagement with the ratchet wheel thereof and can be forced into engagement by gripping of a handle mounted lever. Rainey employs a coaxially disposed rotatable handle section which reverses the ratchet direction of the tool by alternately engaging multitoothed wedges with the ratchet wheel thereof. By placing the handle control in an intermediate position, a condition is presented where neither wedge engages the ratchet wheel and the device can freewheel. A lockup mode is not provided and engagement between the wedge shaped pawls and the ratchet gear is relatively imprecise and causes great strain on the head portion of the ratchet tool case. Zeckzer, through a handle mounted control, engages alternately a pair of pawls to permit ratchet action in two directions. An intermediate position is provided wherein the ratchet portion of the wrench can freewheel and lockup is provided through use of an independent rod which is urged by a separate control to lock the ratchet when the ratchet is disposed in a certain preselected position. Lockup in a single position only may be quite satisfactory for an open-end ratchet wrench, but is not at all desirable for a socket drive wrench type tool. Additionally, the Zeckzer apparatus is rather complex in that three control rods are required.
Other ratchet wrenches such as those taught in U.S. Pat. Nos. 349,007 issued to Sinclair on Sept. 14, 1886; 743,942 issued to Sinclair on Nov. 10, 1903; 581,427 issued to Olson on Apr. 27, 1897; 1,177,764 issued to Dodge on Apr. 4, 1916; 2,003,346 issued to Dodge on June 4, 1935; and 2,590,387 issued to Dodge on Mar. 25, 1952 also teach handle access controls for ratchet wrenches, some of which selectively permit both of the pawls thereof to engage the ratchet wheels thereof to lock the wrench. Each of these apparatuses uses a pawl configuration wherein the pawls either individually and alternately engage a ratchet wheel or both engage a ratchet wheel at the same time to provide a lockup mode. Olson and Dodge ('387) cannot be locked up since only one of the pawls thereof can engage the ratchet wheels thereof at one time. In Dodge ('764) and Sinclair ('007, '942) both pawls can be permitted to engage the ratchet wheel thereof at the same time to lock up the ratchet wrench. The two Dodge patents ('764, '346) both teach stem type controls longitudinally disposed in the handle of the wrench to effect pawl movement. Nonetheless, both of these wrenches use relatively delicate single toothed pawl arrangements and no use of a multitoothed pawl is shown or suggested. Additionally, freewheeling through disengagement of both pawls is not provided.
The four desirable functions, clockwise and counterclockwise ratcheting, freewheeling and lockup are provided in U.S. Pat. Nos. 1,236,802 issued to Willer on Aug. 14, 1917; and 3,867,855 issued to Siebert on Feb. 25, 1975. However, these functions are achieved in a very dissimilar manner in comparison to the apparatus of the present invention. Willer teaches a wrench which has independently sliding pawls that can be individually engaged or disengaged irrespective of the condition of the other pawl and therefore two controls must be manipulated to achieve the desired function. Siebert teaches a lever actuated ratchet wrench which employs a sliding pawl assembly that can be selectively engaged or disengaged with the ratchet gear thereof. Through manipulation of this lever in combination with a ratchet direction control, locking and freewheeling functions can be employed. However, this device employs relatively fragile single toothed pawls and has an excessive number of mechanical parts which speak against long lasting durability and reasonable manufacturing costs.
The present invention overcomes the problems associated with the prior art by providing a socket drive wrench which provides clockwise and counterclockwise ratcheting functions as well as lockup and freewheeling modes all selectable through a simple handle mounted control that actuates a pair of multitoothed pivoted pawls which are disposed about a ratchet gear which positively and effectively engages the same.